Announce the start of the switchover on Slack
Send a message @channel to digital_general & clir_bredig_team
Disable logins on old site
Eddie will take care of this part:
Merge this PR to staging, then production. Wait for the management server to apply it to old-staging, then old-prod.
This should also end all the sessions, so everyone will be kicked out.
Pull database from old-prod to new-prod and reindex
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